On Tue, Apr 16, 2013 at 11:37 AM, Alexander Spyridakis <a.spyridakis@xxxxxxxxxxxxxxxxxxxxxx> wrote: > On 16 April 2013 17:59, Christoffer Dall <cdall@xxxxxxxxxxxxxxx> wrote: >> On Mon, Apr 15, 2013 at 2:52 AM, Alexander Spyridakis >> <a.spyridakis@xxxxxxxxxxxxxxxxxxxxxx> wrote: >>> I've run on this problem before, while trying to run KVM guests on A7 cores. >>> >>> For some reason the 3rd A7 hangs in arch/arm/kvm/init.S, on the instruction >>> that updates HSCTLR between the two isbs on __do_hyp_init (mcr p15, 4, r0, >>> c1, c0, 0). If you boot the system with maxcpus=4 then init_hyp_mode() will >>> not hang on the A7 cluster. Other than that from my limited testing KVM on >>> A7 works on a usual linux guest. I also tried to only boot the 3rd A7 core >>> to rule out any racing issues, but still the same behaviour applies. >>> >> You lost me on the maxcpus=4 and racing point here. If it works with >> maxcpus=4 then it works with two A7s, right? Why would running with >> maxcpus=3 (ie. one A7) rule out any race condition? > > maxcpus=3 would still work (only one A7), but I didn't test it that > way. To make sure and avoid any race conditions from other cpus, I > changed the bootwrapper to explicitly boot only the 3rd A7 (rest of > the cpus being in an infinite loop) and it would still hang. Booting > only the 1st or 2nd A7 core by the same method would work as expected > (no hang in __do_hyp_init_). > so work as expected, as in it doesn't work... Hence the confusion. I don't think this is racy in any way, but for the record, you still have a couple of other A15s running here, so you can't completely rule out races based on your experimental approach, but I really don't think that's the issue anyhow. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm